Influence of growth conditions on exchange bias of NiMn-based spin valves

Abstract

As shown in previous investigations, a correlation between a NiMn-based spin valve's thermal stability and its inherent exchange bias exists, even if the blocking temperature of the antiferromagnet is clearly above the heating temperature and the reason for thermal degradation is mainly diffusion and not the loss of exchange bias. Samples with high exchange bias are thermally more stable than samples with low exchange bias. Those structures promoting a high exchange bias are seemingly the same suppressing thermally induced diffusion processes (A. Wienecke and L. Rissing, “Relationship between thermal stability and layer-stack/structure of NiMn-based GMR systems,” in IEEE Transaction on Magnetic Conference (EMSA 2014)). Many investigations were carried out on the influence of the sputtering parameters as well as the layer thickness on the magnetoresistive effect. The influence of these parameters on the exchange bias and the sample's thermal stability, respectively, was hardly taken into account. The investigation described here concentrates on the last named issue. The focus lies on the influence of the sputtering parameters and layer thickness of the “starting layers” in the stack and the layers forming the (synthetic) antiferromagnet. This paper includes a guideline for the evaluated sputtering conditions and layer thicknesses to realize a high exchange bias and presumably good thermal stability for NiMn-based spin valves with a synthetic antiferromagnet.

Recent Developments of Magnetoresistive Sensors for Industrial Applications

“…Using the exchange bias field as an indicator for layer stacks featuring a high thermal stability, several parameter studies were conducted to determine the deposition parameters and layer thicknesses, which provoke a high exchange bias and presumably higher thermal stability. H eb -values of 80 kA/m could be realized [ 91 ].…”

Study of the effect of the deposition rate and seed layers on structure and magnetic properties of magnetron sputtered FeNi films

“…Furthermore, the structure of sputtered thin films depends significantly on the material of the seed layers on which a film is deposited [5][6][7][8] (Fig. 1a).…”